Alloys



nited States Patent 2,888,741 ALLOYS William E. Knapp, Pittsburgh, andWilbur T. Bolkcom, Allison Park, Pa., assig'nors toAmericanMetallurgical Products Company, Pittsburgh, Pa;, a corporationof Pennsylvania No Drawing. Application March 22, 1955 Serial No.496,058

7 Claims. (Cl. 29-194) This invention relates to alloys and particularlyto an alloy of copper and rare earth elements having unique andsurprising properties and advantages in metallurgical applications.

Alloys of rare earth with ferrous and related metals are old and wellknown and have been used for a great variety of purposes. The additionof the rare earth elements to such materials has, however, been an everpresent problem. Many types of rare earth addition materials have beenproposed with varying degrees of success. The most generally usedaddition alloy for incorporating the rare earth elements into matrixmetals such as iron has been the mixed rare earth alloy commonly calledmischmetal and consisting of between about 40 to 60% cerium, about 20 to35% lanthanum and the balance a mixture of the scarcer rare earthelements such as praseodymium :and neodymium. Mischmetal melts atapproximately 1450 F. and requires some time in order to obtainsatisfactory dispersion in a steel bath.

We have discovered a new alloy which may be used as an additive alloy inmetallurgical purposes and which has further surprising utility as abrazing alloy.

The alloy of this invention may fall within the following broad range:

Copper About 8% to about 20%. Mischmetal Balance.

Preferably, however, the alloy of this invention is limited to the rangeof Copper About 13% to about 17%. Mischmetal Balance.

In a preferred specific composition the alloy will be made up of- CopperAbout 15%. Mischmetal Balance.

An alloy made according to this invention will melt in the range ofabout 700 F. to 800 F. as compared with melting temperatures of about1450 F. for mischmetal and about 2000 F. for copper.

Preferably the alloy of this invention is cast into small pelletsweighing approximately 1 ounce apiece. In this form the alloy can beadded to rapidly cooling masses of metal such as steel at the time ofteeming into ingots.

This rapidly melting, low temperature rare earth alloy permits rareearth additions to be made to a great variety of molten metals withunusually small losses. For example the improved workability obtained byan addition of two pounds per ton of standard mischmetal added to grade310 steel can be obtained with the addition of one pound per ton or lessof the present alloy. This surprising increase in efiectiveness of ourpresent alloy appears to be the result of its low melting tem peratureand its ability to disperse rapidly in molten metals thereby preventinghigh volatilization losses.

The alloy of this invention has great utility as a lice brazing alloysince it melts at a temperature several hundred'degrees' below thelowest melting temperature of ordinary brazing alloys or silver soldersbut has approximately twice their tensile and shear strengths. Presentlyused' brazing materials 'w'hichinclude copper require temperaturesin-excess of2100" F. for proper use. Copper-zinc base-brazing -allbys'generally require temperatures in excess of 1800 Neithei of'the'se wellknown brazing alloys issatisfactory for joining=stel which has beenheat-treated and tempered to give high tensile strengths because of thehigh temperature required to make the joint. The alloy of our invention,on the other hand, may be used in making such joints without anydeleterious effect on the tempered steel and with the production of ajoint which is actually higher in tensile and shear strength than onemade by conventional brazing alloys and this despite the fact that thesteels being joined have been tempered to give tensile strengths of150,000 p.s.i. or higher. In such brazing or joining applications thepreferred alloys are those falling with the limited range of Copper 13%to 17%. Mischmetal Balance.

In the alloy of this invention any of the rare earths alone or incombinations differing from mischmetal may be substituted for themischmetal without detracting from the effectiveness of the alloy. Forexample cerium or lanthanum may be substituted alone or in combinationfor mischmetal in the alloys of this invention.

While we have illustrated and described certain preferred embodiments ofour invention it will be understood that it may be otherwise embodiedwithin the scope of the following claims.

We claim:

1. An article comprising two or more metallic members and the solidifiedproduct of a fused alloy consisting essentially of about 8 to 20% copperand the balance mischmetal, the fused adjacent surfaces of the membersbeing joined by said fused alloy.

2. An article comprising two or more metallic members and the solidifiedproduct of a fused alloy consisting essentially of about 13 to 17%copper and the balance mischmetal, the fused adjacent surfaces of themembers being joined by said fused alloy.

3. An article comprising two or more metallic members and the solidifiedproduct of a fused alloy consisting essentially of about 15% copper andthe balance mischmetal, the fused adjacent surfaces of the members beingjoined by said fused alloy.

4. A method of brazing metal members comprising the steps of heating themetal members to be brazed, applying thereto a pool of molten alloy ofabout 8 to 20% copper and the balance mischmetal, heating to fuse thepool of molten alloy and an adjacent surface of the member to be brazedand cooling to form the completed brazed member.

5. A method of brazing metal members comprising the steps of heating themetal members to be brazed, applying thereto a pool of molten alloy ofabout 13 to 17% copper and the balance mischmetal. heating to fuse thepool of molten alloy and an adjacent surface of the member to be brazedand cooling to form the completed brazed member.

6. A method of brazing metal members comprising the steps of heating themetal members to be brazed, applying thereto a pool of molten alloy ofabout 15% copper and the balance mischmetal, heating to fuse the pool ofmolten alloy and an adjacent surface of the member to be brazed andcooling to form the completed brazed member.

7. An article comprising a. metallic member and the solidified productof a fused alloy consisting essentially of about 8 to 20% copper and thebalance mischmetal, said alloy being joined with the fused adjacentsurface of the metallic member.

References Cited in the file of this patent I UNITED STATES PATENTSDavignon June 21, 1949 Crome Dec. 16, 1952 Kent June 16, 1953 HenselMar. 5, 1956 Drummond Mar. 11, 1958 FOREIGN PATENTS France ......1 Apr.16, 1952 OTHER REFERENCES 10 International Zeithschrift furMetallographie, vol. 7, December 1914\September 1915, pages 174-212.Pages 191 and 208-212 relied on.

Zeitschrift fiur Metallkunde, vol. 35, Issue 6, February 1943, pages29-42 inclusive. Page 40 relied upon.

1. AN ARTICLE COMPRISING TWO OR MORE METALLIC MEMBERS AND THE SOLIDIFIEDPRODUCT OF A FUSED ALLOY CONSISTING ESSENTIALLY OF ABOUT 8 TO 20% COPPERAND THE BALANCE MISCHMETAL, THE FUSED ADJACENT SURFACES OF THE MEMBERSBEING JOINED BY SAID FUSED ALLOY.